Compressed-air brake for railway trains and the like



July 7, 1925;

I. DROLSHAMMER COMPRESSED AIR BRAKE FOR RAILWAY TRAINS AND mm LIKE Filed Aug. 22, 1925 2 Sheets-Sheet 1 Fig. 1.

HE LIKE 2 Sheets-Sheet 2 July 7, 1925.

Patented July 7, 1925.

IVAR DROLSHAMMER, or DBAMMEN, NORWAY.

I COMPRESSEDPAIR BRAKE FOR. RAILWAY TRAINS AND THE 1.11m.

Appli ation. filed August 22, 1923, Serial No. 658,791.

To all whom it may concern":

Be it known thatI, IVAR DROLSHAMMER, a citizen of Norway, and resident of Dram.- men, Norway, have invented certain new and useful Improvements in Compressed- Air Brakes for Railway Trains and the like, of which the following is a specification.

The leading idea of Patent N 0.-1,4O1,325, to regulate proportionally the. pressure stages of air brakes as well on pulling the brake as on releasing is here accomplished by means of'slide valves; these have also proved to be useful throughout in form of ground-in piston-slides, by which an absolutely exact regulation is obtained. The

peculiarity of such slides to show little leakage in working, has normally no influence, as the entire device is inexhaustible in so far as losses of pressure are continually replenished fromthe main-s-u'pply-pipe, the

supply of compressed air being thus independent of the supply by the auxiliary airreservoir.

The invention is based on the perception that these leakages of such compressed-airbrakes may attain a certain influence, in the case of a fracture of couplings and in connection therewith the interruption of the supply of compressed air by the main-pipe. In this case however the working of such brakes is entirely dependent on the quantity of compressed air in the auxiliary reservoir. This reservoir however may be exhausted by leakages of the control-elements, and the special idea of this invention is to remedy thisexceptional case. To that end the control-apparatus is constructed in a way that it-in the ultimate position, corresponding to the absolute exhaustion of compressed air in the main-pipecuts off a second'time the air-exhaustof the brake-cylinder. This is achieved properly by valves which press against each other, and in the best manner by soft packings. -So in normalworking all advantages of the control by slides are guaranteed, while for the mentionedexceptional case the troubles caused by the characteristics of the controlling elements are removed.

To accomplish this haust it is necessary to close all ways by which air may escape withinthe apparatus itself, so that two or even three places are to be tightened, To secure the proper work cutting-ofl -the-exr ing of these tightening-places, there is a special method usedaccording to this in vention.

The invention is shown in two constructions (Fig. 1 and Fig. 2), both longitudinal sections through thepressure-controller of compressed-air-brakes.

The control-piston 10 is within the coil of the double-spring 11 connected to the rod 12 and the spring-holder 13. Along the pistonrod 14 moves the slide-valve 15, which is supported by spring16 against therpiston 10. The slide-valve 15 regulates the supply of compressed air from the auxiliary reservoir, which enters the brake-cylinder from the channel 27 through cock 35 and the channel 17. The function of the brake corresponds generally to that of the the wellknown Drolshammer system. The exhaust of compressed air from the brakecylinder is effected by the small channels 18, 18 parallel to the axis of the cylinder and by the transverse borings 20, 20, which are held free in the down-position (shown in the figures) by the slide-valve 15. Connected with the slide-valve is plate 21, which holds the packing 22 in a groove. Normally this plate 21 with the packing 22 is removed so far from the mouths of the channels 18, 18, that the exhaust of the brake-cylinder is able to escape by streamingthrough the channels 18,18 round plate 22 and through the space between plate 22 and the partitionplate 23 to the exhaust 24.

A second packing 26 is attached to the rod 14 by means of plate 25. In the up-posi its regulating work of supplying the brake' cylinder with compressed air, thereby effect ing the maximum of braking-power in the brake-cylinder and always admitting air by a counter-movement from the auxiliary reservoir through pipe 27, if the maximumpressure in the cylinder decreases by small leakages. If, however, the auxiliary reservoir is so far exhausted, that it is no longer brakes the dillerence' of able to refill the brake-cylinder to the maximum of pressure, this counter-pressure cannot balance the pressure of spring 16, so that the slide-valve 15 moves into its upposition, thereby bringing the packing 21 into effect. This may be supported and also its earlier movement effected by exhaust-air, escaping through the channels 18, 18, and causing a pressure in the space between the cylinder 19 and the partition-plate 23 be cause of the prevention of the exhaust-air from escaping through the rod-passage in the partition-plate 23, which is tightened by the packing 26.

To accomplish the solution oi the problem of tightening, the piston may be fitted with another packing that prevents the escape of compressed air along the piston 10. To this end the piston is fitted with a leather-collar 28, which normally (i. e. in

the case of pressure above the piston) is pressed off the wall of the cylinder 19, so that the free movement of the piston is not interferred with. 'On strongly pulling the pressure however inverts, because the pressure above the piston 1O nearly or totally ceases, so that the super-pressure now working from the in terior of the cylinder presses the leathercollar 28 against the wall oi the cylinder.

In the construction according to Fig. 2 the leather-collar is dispensed with by fitting the piston on both its passages out of the cylinder with packings in the form of valve-plates, by which the cylinder is closed. So the desired closing is effected by a simple method of pressing the packi-ngs against each other, while the free movement of the piston in its intermediate positions is not interfered with. The two valve-plates being attached to the same rigid object on the openings for the piston-rod, here exist two conditions of support, i. e. it is doubtful which of the valvepl'ates presses on its seat as the distribution of pressure in the cylinder cannot be predicted.

This special problem is solved by connecting one of the two valve-plates elastically with the plston-rod tion totpe piston-spring. By these means the yielt ing valve-plate closes first the respective passage while after still more pressure exerted on its spring by the spring 11 of the piston, the other valve-plate is also brou'ght into the desired position, the distribution of pressure being always balanced thereby. In principle the construction of the brake, accordin to Fig. '1 is the same as in Fig. 2. The difference is, that in the design Fig. 2 the longitudinal borings 18, 18 in the cylinder 19 are replaced by simple transversal borings 18, 18 in the slide valve opening below the cylinder 19. At the passage of the piston-rod 12, the valve-plate by means of a spring. which is placed in a. determlnated rela- 31 in form of a leather-packing is supported by a screwed-on cap 33, while at the opposite pass-age of the rod 14 the partition-plate 23 is constructed @as an annular valve-seat. The rod 14 is connected with the valve-plate 25, which bears the leather-ring 26 by the spring 80. The cap 32 fastening the leatherpacking 26 to the valve-plate forms the valve-guard for the valve-plate, relative to the rod 14, touching the end of this rod.

The piston 10 moving up, corresponding to a. decrease of the air-pressure in the mainpipe according to the maximum of the braking-eilect, t'. e. in case of damage to the main-pipe the plate 26 presses first of all against the annular valve-seat 28, thus closing the exhaust, causing air-pressure against the free end of the slide-valve 15, whereby it is balanced and pressed upwards by the released power of spring 16, thus con necting the auxiliary reservoir with the brake-cylinder. 'The slide-valve 15 being closely pressed against the end of the cylinder 19 and tightened by the packing 22, the slide-spring 16 presses the piston-rod 14 down, because the spring power is no longer balanced by the pressure in the brakecylinder, resulting in the pressing up of the piston because of the closing of the exhaust.

The cap 32, forming thevalve-guard 'for plates 25 or 26, surrounding the rod 14, has still another destination. The pressure in the brake-cylinder passing into thec'ap cannot escape, as the cap is-closed all round; only the interior is set under pressure. So the solution of the otherwise ditficult problem of tightening the movable plate 25 to the rod 14 may be dispensed with.

Claims.

1. Control-valve for air-brakes, by which besides the normal tightening by means of slides, effective during the full stroke of the control-elen'ie'nts under the pressure-conditions corresponding to the maximum of brake-power, an auxiliaryclosing of the exhaust of the cylinder is effected, so that in this case two tightening-elements are joined up in serles.

'2. Control-valve according to claim 1, in which the auxiliary tlg'llt'el'lil lg of the exhust in the ultimate position of the piston is eiiected by compression of tightening-elements in form of valve-plates, so that the free movement of the control-elements during their stroke is not injured.

3. Control-valve according to claim 1, in which the rod of the control-piston is connected with a plate bearing a packing-ring, that on escaping of the air-pressure and releasing of the piston-spring presses against the partiton-pl-ate, 'e'ilecting the closure of the cylinder of t 1e co1 1t rol-piston, so that its central aperture for the exhaust is closed.

4. Control-valve according to claim 1, by

which a second closing of the exhaust by means of valve-plates is effected by the controlslide movable against the controlpiston under the action of the spring.

5. Control-valve according to claim 1, by Which besides the auxiliary tightening of the exhaust-side of the cylinder of the control-piston and control-valve such tightening is effected also on the opposite side thereof. v

6. ,Control-valve according to claim 1, in which the control-piston closes both the front-openings of its cylinder .in its ultimate position, a distinct distribution of tightening presure is obtained by connecting the one valve-plate by a spring with the piston.

7. Control-valve according to claim 1, the power and the strain of the spring of the movable valve-plate andits Valve guard being so arranged, that at first the valve-plate closing the exhaust presses against its seat, While under corresponding compression of its spring noW the tightening at the other frontend of the cylinder, of the control-piston and the control-slide is eflected. i

8. Control-valve according toclaim 7, in which the stop of the movable valve-plate is efi'ected by a valve-guard in form of a closed cap, surrounding the abutment of the piston rod and supplementing the valve-plate, penetrated by the piston rod.

' In testimony whereof I aflix my signature.

IVAR DROLSHAMMER.

Witnesses: I

MERL N ORDHENRY, W. CARL PFLFER. 

